In Millennium, people travel from the future to the past, grabbing people who will never be missed due to some sort of catastrophe. For example, if a house will burn down with no survivors, the people can be saved.

However, to make sure that the timestream is undisturbed, it is necessary to replace the person with a duplicate body (called a "wimp").

But there were scars they wanted the wimp to have. The only way to make those is with a timepress field. When everybody was ready they plugged feedlines from big nutrient tanks into the wimp, connected her ureter and anus to evacuator lines, and jumped back.

The blue glow of the Gate surrounded the wimp. It began to breathe so fast the chest was a blur. Its hair and fingernails grew visibly. It used nutrient fluid so fast that it had to be pumped in, and it emitted urine in a pulsed, pressurized stream that hissed into a tank on the floor. In ten seconds it grew six months older. The scars healed normally.